CA1277747C - Control system for a crane - Google Patents
Control system for a craneInfo
- Publication number
- CA1277747C CA1277747C CA000539497A CA539497A CA1277747C CA 1277747 C CA1277747 C CA 1277747C CA 000539497 A CA000539497 A CA 000539497A CA 539497 A CA539497 A CA 539497A CA 1277747 C CA1277747 C CA 1277747C
- Authority
- CA
- Canada
- Prior art keywords
- crane
- speed
- control
- boom
- load
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B66—HOISTING; LIFTING; HAULING
- B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
- B66C23/00—Cranes comprising essentially a beam, boom, or triangular structure acting as a cantilever and mounted for translatory of swinging movements in vertical or horizontal planes or a combination of such movements, e.g. jib-cranes, derricks, tower cranes
- B66C23/88—Safety gear
- B66C23/90—Devices for indicating or limiting lifting moment
- B66C23/905—Devices for indicating or limiting lifting moment electrical
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Control And Safety Of Cranes (AREA)
- Fluid-Pressure Circuits (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The invention relates to a system for controlling the boom of a hydraulic crane, the crane being provided with at least one load sensor on the basis of which the speed of the boom is controlled so that the greatest permissible speed of the boom increases with decreasing load and correspondingly decreases with increasing load.
According to the invention, in order to reduce the dynamic stresses exerted on the crane, the oil flow of the hydraulic actuating means is controlled by directly adjusting the speed of the movements of the valves of the actuating means on the basis of a speed instruction of the boom and on the basis of a load signal and by filtering such speed instructions which indicate valve movement speeds exceeding a predetermined value.
The invention relates to a system for controlling the boom of a hydraulic crane, the crane being provided with at least one load sensor on the basis of which the speed of the boom is controlled so that the greatest permissible speed of the boom increases with decreasing load and correspondingly decreases with increasing load.
According to the invention, in order to reduce the dynamic stresses exerted on the crane, the oil flow of the hydraulic actuating means is controlled by directly adjusting the speed of the movements of the valves of the actuating means on the basis of a speed instruction of the boom and on the basis of a load signal and by filtering such speed instructions which indicate valve movement speeds exceeding a predetermined value.
Description
~Z;Pir'7~7 Dynamic loads have to be taken into account in the strength dimensioning of the structure of cranes. Such loads are due to the accelerations and decelerations of the boom system itself and particularly those of a load to be lifted.
Prior art systems determine the highest permissible speed of the boom system of a crane by means of a hydraulic pump providing a volume flow set to a predetermined maximum level specific for each particular crane. In such prior art systems the volume flow provided is distributed to the different actuating means, ma nly to the hydraulic cylinders, by means of control valves controlled mechanically by means of levers.
A serious drawback of such prior art systems has been that the greatest permissible load and speed of the crane have been fixed and independent of each other, i.e.
it has been necessary to dimension the crane in view o~ a situation when a maximum load is displaced at a maximum speed, which has been a frequently occurring situation in practice. It has been possible to effect the starting and stopping movements of the crane very rapidly, on account of which the crane structure is often caused to vibrate during the displacement of the load. Any attempts made by the operator to compensate for the vibration have generally only increased the vibration, because the control movements and the specific frequency of the crane structure together have created an unsuppressed vibration.
The abovementioned drawback is due to the fact that the movements of the valves of the actuating means of the crane, mainly those of the hydraulic cylinders, have been controlled directly, mechanically. The prevailing opinion among those skilled in the art has been that it is impossible to affect the accelerations by reducing the opening and closing speeds of the control valves, because the control of the crane would thereby require anticipation and would become inaccurate and even dangerous.
1277'747 U.S. Patent No. 4,006,347 suggests that the load should be taken into account by retarding the movement of the crane boom in the vertical plane when the boom swings from above towards a horizontal position, and, correspondingly, accelerated when the boom moves from below upwards. The control, however, is carried out indirectly by means of an additional valve which bypasses part of the volume flow past the valve of the hydraulic cylinder back to the tank, as a result of which the control is inaccurate, particularly at stages for starting and stopping the boom.
An object of the present invention is to provide a new control system in which the dynamic loads exerted on the crane are taken into account better than in prior art systems.
According to the present invention then, in a system for controlling the boom system of a hydraulic crane, the crane is provided with at least one load sensor which provides measuring data on the basis of which the speed of the boom is controllable so that the greatest permissible speed of the boom increases with decreasing load and correspondingly decreases with increasing load, and, in order to reduce the dynamic stresses exerted on the crane, the oil flow of the hydraulic actuating means of the crane is controllable by directly adjusting the speed of the movements of valves of the actuating means on the basis of a speed instruction of the boom and of a load signal and by filtering out such speed instructions which indicate valve movement speeds exceeding a predetermined value.
Thus the dynamic stresses caused by the accelerations of the load are reduced in the control system according to the invention by preventing the control valve from opening and closing too rapidly and by decreasing the speed of the movements of the crane at high loads in particular. The filtering of the control movements of the operator decreases the accelerations, compensates for the 12~7747 disadvantageous effects of erroneous movements and improves the control properties of the crane system. By virtue of reduced variation in the dynamic stresses, the lifting power of the crane can be increased and the steering properties improved; further, the durability of the boom structures can be improved or the structures can be lightened.
The hydraulic valves may be controlled electrically. The oil flow, controllable by an operator, may then be regulated by varying the electric control signal on the basis of the load data. The volume of oil that flows is thereby controllable by means of the same valve by means of which the crane is generally controlled.
An advantage of this arrangement is that the number of the hydraulic components need not be increased.
The control system of the crane can preferably be constructed in the following way The system may comprise a programmable control unit, which may for example be digital, for effecting the adjustment of the maximum speed on the basis of the information obtained from the load sensor. The control unit comprises a filter element, which may for example be digital, for monitoring the speed of movements of control lever means filtering out excessively high frequencies and effecting the accelerations and decelerations in a stepped manner. Control and monitoring functions of the cGntrol unit may be programmed separately for each crane and actuating means.
In drawings which illustrate embodiments of the invention, Figure 1 is a side view of a crane, Figure 2 is a general diagram of the control system, Figure 3 is a block diagram of the electrical control unit, 12~77747 Figure 4 is a block diagram of a preferred specific program stored in the program memory of the control unit, and Figure 5 shows an example function between pressure and speed.
The crane shown in Figure 1 comprises a base 1, a pillar 2, a lifting boom 3, a displacing boom 4 and an extension 5 thereof, a gram 6, a lifting cylinder 7 and a displacing cylinder 8.
The load of the crane exerts the heaviest stress on the pillar 2 and the lifting cylinder 7, on account of which at least one load sensor according to the system is preferably positioned either in the pillar 2 or in the lifting cylinder 7. The load sensor may, for instance, measure the pressure in the lifting cylinder 7, or in its feeding hose, or a strain gauge may be attached to the surface of the pillar 2.
Sensors suited for the purpose are readily available; their structure and operation need not be more closely described here.
In Figure 2, the block 9 represents an electronic control unit, the block 10 a control valve system and the block 11 controllable actuating means (hydraulic cylinders). The arrow 12 designates a supply wire of a power source, the arrow 13 speed instructions given by an operator, the arrow 14 load data, the arrow 15 a control signal of the valve and the arrows 16 and 17 the oil flow.
In Figure 3, the reference numeral 18 designates a load sensor which provides a voltage signal 19 which is modified in an analog to digital converter 20 to be applied to a microprocessor 21 in digital form. Speed instructions 23 obtained from a control potentiometer 22 are likewise modified in the A/D converter 20 to be applied to the microprocessor 21 in digital form. On the basis of the speed instructions 23 and the load signal 14, the microprocessor 21 performs the control and filtration ~, calc:ulations of the speed instructions according to a control program stored in an EPROM 24. The modified speed inst:ructions are transmitted to the control valves 26 from a serial transmission controller 27. The control quantity of the valve may also be an analog electrical signal, a digital to analog converter being used in place of the serial transmission controller.
One preferred embodiment will now be described in more detail.
The system may comprise a digitally controllable control valve, control electronics, electrical control levers and a pressure sensor.
Three actuating means (hydraulic cylinders) can be controlled, either simultaneously or separately, by means of two control levers, which are preferably attached near to a driver's seat. Three potentiometers are positioned in connection with the control lever in such a manner that when the lever is turned, two of the potentiometers are deviated from their mid position to one direction or the other, and when press buttons provided in the lever are pressed, the third potentiometer is deviated.
All the potentiometers are connected in parallel to a direct-current voltage of, for example, 5 V, so that wnen the potentiometer is in the mid position, the output voltage will be 2.S V. Accordingly, six output voltages varying between O V and 5 V are obtained from the control lever, depending on the position of the control levers at each particular moment. When the output voltage is less than 2.5 V, the hydraulic cylinder is retracted and, correspondingly, when the voltage exceeds 2.S V, the hydraulic cylinder is displaced outwards, i.e. the length thereof increases. When the voltage is 2.5 V, the cylinder stays in place. The more each output voltage approaches 0 V or 5 V, the greater the magnitude of the speed instruction the respective actuating means receives.
1~
The control voltages are connected to a control unit in which the data is modified and processed and transmitted further to the control valves. The control unit comprises e.g. a microprocessor, an analog to digital converter, a program memory, a working memory, a serial transmission controller and an oscillator crystal. The program memory is of the Read Only type, being programmed by means of a separate programming device. The data stored in the program memory is preserved over breaks occurring in the flow of electric current. The control program is an endless program loop which is repeated many times per second when the device is in operation.
The block diagram of the program stored in the program memory is shown in Figure 4. When voltage is connected to the control unit, the processor starts to perform the program stored in the program memory. The processor first performs the initializations required by the interrupting controller and by the serial transmission controller, by writing predetermined syllables in the registers of said controllers. The registers are located in a so called random access memory in which the stored data disappears when a break occurs in the flow of electric current.
The performance of the program loop is started by reading the control signals. These control signals include the control voltages (six in number) from the control levers and the voltage from the pressure sensor. The pressure sensor is a strain gauge type sensor the maximum output of which is 100 mV for a supply voltage of 10 V, so that the pressure signal is amplified to a level of 0 to 5 V before it is applied to the analog to digital converter.
The analog to digital converter converts the voltages corresponding to the control signals into a digital form (with 0-225 decimals). Thereafter the pressure signal is filtered so as to determine the average pressure level in the lifting cylinder. Hence, the pressure peaks caused by 'I'"
.~
~m47 the swingings of the load do not affect this level. The filtering prevents the control system from oscillating at its resonant frequency due to swinging of the load. The filtering is effected by means of a mathematical algorithm in which a new filtered value is obtained by adding the difference of a rating and a previous filtered value to the previous filtered value, the difference being multiplied with a predetermined parameter; in the form of a formula X2 = Xl + a* (~ - Xl), wherein X1 = previous filtered value, X2 = new filtered value, a = parameter, ~ = rating. By varying the parameter a, a desired filter function is obtained. In practice, the filtering causes the new filtered value X2 to obtain the rating in a stepwise manner, i.e. in a predetermined rise time specific for the filter.
Thereafter the control signals obtained from the control levers are filtered by means of the above-mentioned algorithm. The filtering parameters of the different control signals can be chosen to meet the requirements of each particular crane. The opening and closing speeds of the desired control valves are reduced by the filtering of the control messages and, as a consequence, the accelerations and decelerations of the actuating means and the load are also reduced.
The adjustment of the speed of movement of an individual actuating means is carried out on the basis of the pressure signal. The control program increases the greatest permissible speed of the actuating means when the pressure signal is decreased and correspondingly decreases it when the pressure signal is increased e.g. according to the function shown in Figure 5. The effect of the pressure signal on the maximum speed of movement of the actuating means may vary from one actuating means to another.
The pressure signals measured initially from the control levers are modified on the basis of the control and loading state of the crane to be applied to the control , ~
~2~7747 valves. At the end of the program loop, the control signals are applied through the serial transmission controller to the valves. The control valve is a valve which can be controlled by means of a control signal in serial form and which may for example be digital. The decoding of the control signals and the adjustment of the control valve to a desired position are carried out in the control valve itself.
The crane usually comprises several control valves for the different movements. In Figure 3, these valves are merely outlined by means of dots 28 for the sake of simplicity. As appears from Figure 3, the operation of all the required valves can be altered by varying the control program so that the desired operation is obtained lS with the actuating means and crane.
Prior art systems determine the highest permissible speed of the boom system of a crane by means of a hydraulic pump providing a volume flow set to a predetermined maximum level specific for each particular crane. In such prior art systems the volume flow provided is distributed to the different actuating means, ma nly to the hydraulic cylinders, by means of control valves controlled mechanically by means of levers.
A serious drawback of such prior art systems has been that the greatest permissible load and speed of the crane have been fixed and independent of each other, i.e.
it has been necessary to dimension the crane in view o~ a situation when a maximum load is displaced at a maximum speed, which has been a frequently occurring situation in practice. It has been possible to effect the starting and stopping movements of the crane very rapidly, on account of which the crane structure is often caused to vibrate during the displacement of the load. Any attempts made by the operator to compensate for the vibration have generally only increased the vibration, because the control movements and the specific frequency of the crane structure together have created an unsuppressed vibration.
The abovementioned drawback is due to the fact that the movements of the valves of the actuating means of the crane, mainly those of the hydraulic cylinders, have been controlled directly, mechanically. The prevailing opinion among those skilled in the art has been that it is impossible to affect the accelerations by reducing the opening and closing speeds of the control valves, because the control of the crane would thereby require anticipation and would become inaccurate and even dangerous.
1277'747 U.S. Patent No. 4,006,347 suggests that the load should be taken into account by retarding the movement of the crane boom in the vertical plane when the boom swings from above towards a horizontal position, and, correspondingly, accelerated when the boom moves from below upwards. The control, however, is carried out indirectly by means of an additional valve which bypasses part of the volume flow past the valve of the hydraulic cylinder back to the tank, as a result of which the control is inaccurate, particularly at stages for starting and stopping the boom.
An object of the present invention is to provide a new control system in which the dynamic loads exerted on the crane are taken into account better than in prior art systems.
According to the present invention then, in a system for controlling the boom system of a hydraulic crane, the crane is provided with at least one load sensor which provides measuring data on the basis of which the speed of the boom is controllable so that the greatest permissible speed of the boom increases with decreasing load and correspondingly decreases with increasing load, and, in order to reduce the dynamic stresses exerted on the crane, the oil flow of the hydraulic actuating means of the crane is controllable by directly adjusting the speed of the movements of valves of the actuating means on the basis of a speed instruction of the boom and of a load signal and by filtering out such speed instructions which indicate valve movement speeds exceeding a predetermined value.
Thus the dynamic stresses caused by the accelerations of the load are reduced in the control system according to the invention by preventing the control valve from opening and closing too rapidly and by decreasing the speed of the movements of the crane at high loads in particular. The filtering of the control movements of the operator decreases the accelerations, compensates for the 12~7747 disadvantageous effects of erroneous movements and improves the control properties of the crane system. By virtue of reduced variation in the dynamic stresses, the lifting power of the crane can be increased and the steering properties improved; further, the durability of the boom structures can be improved or the structures can be lightened.
The hydraulic valves may be controlled electrically. The oil flow, controllable by an operator, may then be regulated by varying the electric control signal on the basis of the load data. The volume of oil that flows is thereby controllable by means of the same valve by means of which the crane is generally controlled.
An advantage of this arrangement is that the number of the hydraulic components need not be increased.
The control system of the crane can preferably be constructed in the following way The system may comprise a programmable control unit, which may for example be digital, for effecting the adjustment of the maximum speed on the basis of the information obtained from the load sensor. The control unit comprises a filter element, which may for example be digital, for monitoring the speed of movements of control lever means filtering out excessively high frequencies and effecting the accelerations and decelerations in a stepped manner. Control and monitoring functions of the cGntrol unit may be programmed separately for each crane and actuating means.
In drawings which illustrate embodiments of the invention, Figure 1 is a side view of a crane, Figure 2 is a general diagram of the control system, Figure 3 is a block diagram of the electrical control unit, 12~77747 Figure 4 is a block diagram of a preferred specific program stored in the program memory of the control unit, and Figure 5 shows an example function between pressure and speed.
The crane shown in Figure 1 comprises a base 1, a pillar 2, a lifting boom 3, a displacing boom 4 and an extension 5 thereof, a gram 6, a lifting cylinder 7 and a displacing cylinder 8.
The load of the crane exerts the heaviest stress on the pillar 2 and the lifting cylinder 7, on account of which at least one load sensor according to the system is preferably positioned either in the pillar 2 or in the lifting cylinder 7. The load sensor may, for instance, measure the pressure in the lifting cylinder 7, or in its feeding hose, or a strain gauge may be attached to the surface of the pillar 2.
Sensors suited for the purpose are readily available; their structure and operation need not be more closely described here.
In Figure 2, the block 9 represents an electronic control unit, the block 10 a control valve system and the block 11 controllable actuating means (hydraulic cylinders). The arrow 12 designates a supply wire of a power source, the arrow 13 speed instructions given by an operator, the arrow 14 load data, the arrow 15 a control signal of the valve and the arrows 16 and 17 the oil flow.
In Figure 3, the reference numeral 18 designates a load sensor which provides a voltage signal 19 which is modified in an analog to digital converter 20 to be applied to a microprocessor 21 in digital form. Speed instructions 23 obtained from a control potentiometer 22 are likewise modified in the A/D converter 20 to be applied to the microprocessor 21 in digital form. On the basis of the speed instructions 23 and the load signal 14, the microprocessor 21 performs the control and filtration ~, calc:ulations of the speed instructions according to a control program stored in an EPROM 24. The modified speed inst:ructions are transmitted to the control valves 26 from a serial transmission controller 27. The control quantity of the valve may also be an analog electrical signal, a digital to analog converter being used in place of the serial transmission controller.
One preferred embodiment will now be described in more detail.
The system may comprise a digitally controllable control valve, control electronics, electrical control levers and a pressure sensor.
Three actuating means (hydraulic cylinders) can be controlled, either simultaneously or separately, by means of two control levers, which are preferably attached near to a driver's seat. Three potentiometers are positioned in connection with the control lever in such a manner that when the lever is turned, two of the potentiometers are deviated from their mid position to one direction or the other, and when press buttons provided in the lever are pressed, the third potentiometer is deviated.
All the potentiometers are connected in parallel to a direct-current voltage of, for example, 5 V, so that wnen the potentiometer is in the mid position, the output voltage will be 2.S V. Accordingly, six output voltages varying between O V and 5 V are obtained from the control lever, depending on the position of the control levers at each particular moment. When the output voltage is less than 2.5 V, the hydraulic cylinder is retracted and, correspondingly, when the voltage exceeds 2.S V, the hydraulic cylinder is displaced outwards, i.e. the length thereof increases. When the voltage is 2.5 V, the cylinder stays in place. The more each output voltage approaches 0 V or 5 V, the greater the magnitude of the speed instruction the respective actuating means receives.
1~
The control voltages are connected to a control unit in which the data is modified and processed and transmitted further to the control valves. The control unit comprises e.g. a microprocessor, an analog to digital converter, a program memory, a working memory, a serial transmission controller and an oscillator crystal. The program memory is of the Read Only type, being programmed by means of a separate programming device. The data stored in the program memory is preserved over breaks occurring in the flow of electric current. The control program is an endless program loop which is repeated many times per second when the device is in operation.
The block diagram of the program stored in the program memory is shown in Figure 4. When voltage is connected to the control unit, the processor starts to perform the program stored in the program memory. The processor first performs the initializations required by the interrupting controller and by the serial transmission controller, by writing predetermined syllables in the registers of said controllers. The registers are located in a so called random access memory in which the stored data disappears when a break occurs in the flow of electric current.
The performance of the program loop is started by reading the control signals. These control signals include the control voltages (six in number) from the control levers and the voltage from the pressure sensor. The pressure sensor is a strain gauge type sensor the maximum output of which is 100 mV for a supply voltage of 10 V, so that the pressure signal is amplified to a level of 0 to 5 V before it is applied to the analog to digital converter.
The analog to digital converter converts the voltages corresponding to the control signals into a digital form (with 0-225 decimals). Thereafter the pressure signal is filtered so as to determine the average pressure level in the lifting cylinder. Hence, the pressure peaks caused by 'I'"
.~
~m47 the swingings of the load do not affect this level. The filtering prevents the control system from oscillating at its resonant frequency due to swinging of the load. The filtering is effected by means of a mathematical algorithm in which a new filtered value is obtained by adding the difference of a rating and a previous filtered value to the previous filtered value, the difference being multiplied with a predetermined parameter; in the form of a formula X2 = Xl + a* (~ - Xl), wherein X1 = previous filtered value, X2 = new filtered value, a = parameter, ~ = rating. By varying the parameter a, a desired filter function is obtained. In practice, the filtering causes the new filtered value X2 to obtain the rating in a stepwise manner, i.e. in a predetermined rise time specific for the filter.
Thereafter the control signals obtained from the control levers are filtered by means of the above-mentioned algorithm. The filtering parameters of the different control signals can be chosen to meet the requirements of each particular crane. The opening and closing speeds of the desired control valves are reduced by the filtering of the control messages and, as a consequence, the accelerations and decelerations of the actuating means and the load are also reduced.
The adjustment of the speed of movement of an individual actuating means is carried out on the basis of the pressure signal. The control program increases the greatest permissible speed of the actuating means when the pressure signal is decreased and correspondingly decreases it when the pressure signal is increased e.g. according to the function shown in Figure 5. The effect of the pressure signal on the maximum speed of movement of the actuating means may vary from one actuating means to another.
The pressure signals measured initially from the control levers are modified on the basis of the control and loading state of the crane to be applied to the control , ~
~2~7747 valves. At the end of the program loop, the control signals are applied through the serial transmission controller to the valves. The control valve is a valve which can be controlled by means of a control signal in serial form and which may for example be digital. The decoding of the control signals and the adjustment of the control valve to a desired position are carried out in the control valve itself.
The crane usually comprises several control valves for the different movements. In Figure 3, these valves are merely outlined by means of dots 28 for the sake of simplicity. As appears from Figure 3, the operation of all the required valves can be altered by varying the control program so that the desired operation is obtained lS with the actuating means and crane.
Claims (6)
1. In a system for controlling the boom of a hydraulic crane, the crane being provided with at least one sensor for load data on the basis of which data the speed of the boom is controllable so that the greatest permissible speed of the boom increases with decreasing load and correspondingly decreases with increasing load, and, in order to reduce the dynamic stresses exerted on the crane, the oil flow of hydraulic actuating means of the crane is controllable by directly adjusting the speed of the movements of valves of the actuating means on the basis of a speed instruction of the boom and of a load signal and by filtering out such speed instructions which indicate valve movement speeds exceeding a predetermined value.
2. A system according to claim 1, wherein the hydraulic valves are controllable electrically and the oil flow controllable by an operator is regulated by limiting the electric control signal on the basis of the load data.
3. A system according to claim 2, wherein the volume of oil that flows is controllable by means of the same valve used for the general control of the crane.
4. A system according to claim 1, comprising a programmable regulating unit for regulating the respective maximum speed, said regulating unit including filter means for monitoring movement speeds of control lever means and for filtering out excessively high frequencies.
5. A system according to claim 4, wherein at least one of said regulating unit and said filter means is digital.
6. A system according to claim 4 or 5, wherein control and monitoring functions of the control unit are programmed separately for each crane and actuating means.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI862627A FI862627A0 (en) | 1986-06-19 | 1986-06-19 | SYSTEM FOER REGLERANDE AV EN KRANS HASTIGHET. |
| FI862627 | 1986-06-19 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1277747C true CA1277747C (en) | 1990-12-11 |
Family
ID=8522818
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000539497A Expired - Lifetime CA1277747C (en) | 1986-06-19 | 1987-06-12 | Control system for a crane |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US4815614A (en) |
| AT (1) | AT402916B (en) |
| CA (1) | CA1277747C (en) |
| DE (1) | DE3719897C2 (en) |
| FI (1) | FI862627A0 (en) |
| FR (1) | FR2600316B1 (en) |
| SE (1) | SE464192B (en) |
Families Citing this family (28)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5297019A (en) * | 1989-10-10 | 1994-03-22 | The Manitowoc Company, Inc. | Control and hydraulic system for liftcrane |
| US5579931A (en) * | 1989-10-10 | 1996-12-03 | Manitowoc Engineering Company | Liftcrane with synchronous rope operation |
| US6758356B1 (en) | 1989-10-10 | 2004-07-06 | Manitowoc Crane Companies, Inc. | Liftcrane with synchronous rope operation |
| US5189605A (en) * | 1989-10-10 | 1993-02-23 | The Manitowoc Company, Inc. | Control and hydraulic system for a liftcrane |
| US5282136A (en) * | 1990-03-30 | 1994-01-25 | Kabushiki Kaisha Kobe Seiko Sho | Vertical releasing control device of crane hanging load |
| US5117992A (en) * | 1991-01-28 | 1992-06-02 | Virginia International Terminals, Inc. | System for learning control commands to robotically move a load, especially suitable for use in cranes to reduce load sway |
| DE4223695C2 (en) * | 1992-07-21 | 1994-12-08 | Weber Anlagenbau Gmbh & Co Kg | Control for pivoting a boom that is variable in its effective length |
| JPH07144884A (en) * | 1993-11-26 | 1995-06-06 | Komatsu Mec Corp | Mobile reach tower crane |
| DE19653579B4 (en) * | 1996-12-20 | 2017-03-09 | Liebherr-Werk Biberach Gmbh | Tower Crane |
| ES2158637T3 (en) * | 1998-09-08 | 2001-09-01 | Palfinger Ag | CRANE. |
| FI109349B (en) * | 2000-07-18 | 2002-07-15 | Timberjack Oy | Method of Boom Control and Boom Control System |
| AT4664U1 (en) * | 2000-10-25 | 2001-10-25 | Veitsch Radex Gmbh | DEVICE FOR RECEIVING AND TRANSPORTING AN OBJECT |
| US6527130B2 (en) | 2001-02-16 | 2003-03-04 | General Electric Co. | Method and system for load measurement in a crane hoist |
| DE10115312A1 (en) * | 2001-03-28 | 2002-10-02 | Man Wolffkran | Controlling crane movements, involves limiting speed and/or acceleration of crane movement by maximum movement depending on deviation of load moment from maximum load moment |
| US6991119B2 (en) | 2002-03-18 | 2006-01-31 | Jlg Industries, Inc. | Measurement system and method for assessing lift vehicle stability |
| US7014054B2 (en) | 2002-07-01 | 2006-03-21 | Jlg Industries, Inc. | Overturning moment measurement system |
| US6994223B1 (en) * | 2002-10-29 | 2006-02-07 | Auto Crane Company | Diagnostic readout for operation of a crane |
| US8005598B2 (en) * | 2003-08-05 | 2011-08-23 | Sintokogio, Ltd. | Crane and controller thereof |
| FI118469B (en) * | 2006-03-31 | 2007-11-30 | Loglift Jonsered Oy Ab | Method and equipment for controlling the crane actuator |
| DE102009032270A1 (en) * | 2009-07-08 | 2011-01-13 | Liebherr-Werk Nenzing Gmbh | Method for controlling a drive of a crane |
| US8272521B1 (en) * | 2009-10-05 | 2012-09-25 | Auto Crane Company | Crane moment load and load delivery system control and method |
| NO337712B1 (en) * | 2010-03-24 | 2016-06-06 | Nat Oilwell Varco Norway As | Device and method for reducing dynamic loads in cranes |
| IT1402191B1 (en) * | 2010-09-23 | 2013-08-28 | Merlo Project Srl | LIFTING VEHICLE. |
| US10647560B1 (en) * | 2011-05-05 | 2020-05-12 | Enovation Controls, Llc | Boom lift cartesian control systems and methods |
| CN103318765B (en) * | 2013-06-21 | 2015-01-07 | 林汉丁 | Hoisting tilt angle, hoisting load or hoisting posture monitoring method and device as well as crane |
| EP3431435B1 (en) * | 2017-07-17 | 2020-04-22 | Manitou Bf | Control of a handling machine |
| US10677269B2 (en) | 2018-08-30 | 2020-06-09 | Jack K. Lippett | Hydraulic system combining two or more hydraulic functions |
| CN110342405B (en) * | 2019-07-25 | 2020-10-02 | 上海振华重工(集团)股份有限公司 | Control method for accurate positioning of container straddle carrier lifting mechanism |
Family Cites Families (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1184052B (en) * | 1959-07-07 | 1964-12-23 | Demag Zug Gmbh | Safety circuit for hoists |
| DE2033469B2 (en) * | 1970-07-07 | 1979-01-18 | Carl Metz Gmbh, 7500 Karlsruhe | Tilting moment-dependent ladder control |
| GB1403046A (en) * | 1972-09-08 | 1975-08-13 | Weimar Kombinat Veb | Load factor safety mechanism |
| DD121915A1 (en) * | 1973-09-28 | 1976-09-05 | ||
| FR2261216A1 (en) * | 1974-02-14 | 1975-09-12 | Tico Ab | Servo-controlled crane overload protection - has derricking ram pressure detector releasing pressure from servo-controls |
| AT343860B (en) * | 1975-02-04 | 1978-06-26 | Krueger & Co Kg | DEVICE FOR CONTROLLING A CRANE JIB DRIVE |
| AT347634B (en) * | 1977-06-10 | 1979-01-10 | Orenstein & Koppel Ag | INDEPENDENT CONTROL FOR DAMPING LOAD VIBRATIONS IN CRANES WITH ROPE HOIST |
| US4178591A (en) * | 1978-06-21 | 1979-12-11 | Eaton Corporation | Crane operating aid with operator interaction |
| US4222491A (en) * | 1978-08-02 | 1980-09-16 | Eaton Corporation | Crane operating aid and sensor arrangement therefor |
| CS201792B1 (en) * | 1978-09-22 | 1980-11-28 | Juraj Sinay | Lifting capacity limiter for lifting machines |
| SE416538B (en) * | 1979-04-02 | 1981-01-19 | Hiab Foco Ab | DEVICE FOR HYDRAULIC CRANES |
| DE3103728A1 (en) * | 1981-02-04 | 1982-09-02 | Fried. Krupp Gmbh, 4300 Essen | Device for improving the operational behaviour of mobile slewing cranes |
| DE3513007A1 (en) * | 1984-04-11 | 1985-12-19 | Hitachi, Ltd., Tokio/Tokyo | Method and arrangement for the automatic control of a crane |
| DE3420596C2 (en) * | 1984-06-01 | 1986-10-02 | Dr.-Ing. Ludwig Pietzsch Gmbh & Co, 7505 Ettlingen | Monitoring and control system for jib cranes |
-
1986
- 1986-06-19 FI FI862627A patent/FI862627A0/en not_active Application Discontinuation
-
1987
- 1987-06-12 CA CA000539497A patent/CA1277747C/en not_active Expired - Lifetime
- 1987-06-13 DE DE3719897A patent/DE3719897C2/en not_active Expired - Lifetime
- 1987-06-15 US US07/062,199 patent/US4815614A/en not_active Expired - Lifetime
- 1987-06-16 AT AT0153087A patent/AT402916B/en not_active IP Right Cessation
- 1987-06-16 SE SE8702506A patent/SE464192B/en not_active IP Right Cessation
- 1987-06-18 FR FR8708550A patent/FR2600316B1/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| FI862627A0 (en) | 1986-06-19 |
| DE3719897A1 (en) | 1987-12-23 |
| FR2600316B1 (en) | 1990-12-21 |
| SE8702506D0 (en) | 1987-06-16 |
| US4815614A (en) | 1989-03-28 |
| FR2600316A1 (en) | 1987-12-24 |
| ATA153087A (en) | 1997-02-15 |
| SE464192B (en) | 1991-03-18 |
| DE3719897C2 (en) | 1999-08-19 |
| AT402916B (en) | 1997-09-25 |
| SE8702506L (en) | 1987-12-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1277747C (en) | Control system for a crane | |
| US6553278B2 (en) | Method for guiding a boom and a system for guiding a boom | |
| KR100392333B1 (en) | Crane | |
| EP0292473B1 (en) | Method for reducing the piston speed, especially in the piston and cylinder assemblies of an excavating machine, and device for carrying out the method | |
| US4907493A (en) | Valve control system for hitch motor | |
| CA2060344C (en) | Control device for work machine | |
| KR930010320A (en) | Actuator automatic speed regulating device and its control method | |
| US6199378B1 (en) | Off-setting rate of pressure rise in a fluid system | |
| US7031883B1 (en) | Spreader | |
| US6244831B1 (en) | Control device for variable displacement pump | |
| US4793308A (en) | Emergency control device for a diesel internal combustion engine with electronically controlled fuel proportioning | |
| KR100442577B1 (en) | Numerical controlling unit | |
| EP0821299A1 (en) | Operational reaction force control device for an operating lever of a working machine | |
| JP2822907B2 (en) | Hydraulic control device | |
| FI75551C (en) | STYRSYSTEM FOER LYFTKRAN. | |
| JP3730801B2 (en) | Directional switching valve controller | |
| JPH10159809A (en) | Flow controller for hydraulic actuator | |
| EP0632789B1 (en) | Hydraulic crane with increased maximum lifting power in the high-position area, and method therefor | |
| JPH0565440B2 (en) | ||
| SU613037A1 (en) | Device for controlling digging mechanism of single-bucket excavator | |
| KR960004630B1 (en) | Control devices of hydraulic machines | |
| JP2634301B2 (en) | Lifting / lowering hydraulic control method for full free mast device | |
| KR0185429B1 (en) | Actuating system of gyratory screen | |
| JP2000355497A (en) | Cylinder control device for cargo handling of forklift truck | |
| KR0183656B1 (en) | Digital type oil-pressure control system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |